Transcript Slide 1

Negative Index/Refraction &
Fabrication + Application
EE235 2nd presentation
May 4th, 2009
Jun Rho
Cloaking & Invisible Man
Refraction & Snell’s law
Snell’s law
sin 1 v1 n2
 
sin  2 v2 n1
Total Internal Reflection
 n2 
 c  sin  
 n1 
1
Negative Index Metamaterials
Refractive Index
n  n1  in2  (e1m1  e 2 m2 )  i (e1m2  e 2 m1 )
where
e  e1  ie 2
 Snell’s
“Practical
Law


Applications”

n1
negative m
materials
e>0
m<0
1
1
SuperLens
sin 
n
n

 p|
HyperLens
sin

n
n
(p = -1 for LHM)
Cloaking
1
2
2
2
1
1
|
2
S
e>0
m>0
most dielectrics
no natural
materials
e<0
m<0
m  m1  i m2

e<0
m>0
metals , ionic
crystals
m
n1
RHM
RHM
RHM
LHM
n2
2
k
S
n2
k
e
Superlens: Principle
Diffraction limit w/o superlens
Diffraction limit w superlens
~

5
~

2

6
X. Zhang et al, Vol. 308, pp 435-441, Nature Materials, 2008
Superlens: Experiment
At wavelength = 365nm
Resolution achieved about 60-90nm
N. Fang et al, Vol. 308, pp1534-5376, Science, 2005
Superlens: Fabrication
1. Cr deposition on a quartz substrate
2. Focused Ion Beam (FIB) patterning
3. Planarization
4. PMMA spacer layer deposition
5. Ag layer deposition
6. Near field photolithography
N. Fang et al, Vol. 308, pp1534-5376, Science, 2005
Hyperlens: Principle
|H|
0.04
Wavelength: 405nm
At wavelength = 365nm
0.02
Diffraction limit w/o hyperlens
1.22   1.22  365nm

 155nm
2 NA
2 1.44
45pairs 10nmAg/10nm Ta2O5(R1:100nm,R2:1000nm)
Object: 50nm separation, 20nm opening
0
Diffraction limit w/ hyperlens
1.22   1.22  365nm

 120nm
NA  M
1.5  2.5
Theoretically, diffraction limit is
overcame. (120m < 150nm)
Images after hyperlens
0.06
0.04
130nm
140nm
150nm
160nm
0.02
Experimental resolution limit?
0
-1500
-1000
-500
0
d (nm)
500
1000
1500
22 pairs (R1: 400nm, R2: 1940nm)
Hyperlens: Experiment
J. Liu et all, Vol. 315, p 1686, Science, 2007
130nm
Hyperlens: Fabrication
1. Cr deposition on the quartz surface
2. Focused Ion Beam (FIB) patterning.
3. HF (BOE) wet etching
4. Remove mask layer
5. Multilayer deposition of Ag and Al2O3
by E-beam evaporator. Finally, the last
Cr layer deposition is followed
Superlens & Hyperlens
Conventional lens
Superlens
(Near field)
Superlens
(Far field)
X. Zhang et al, Vol. 308, pp 435-441, Nature Materials, 2008
Hyperlens
Metamaterials: Principle & Fab.
Negative Permeability (µ)
k
H
k
E
Negative Permittivity (ε)
Negative Index (LHM)
H
E
Wire Grid Polarizer
RLC Circuit
S. Zhang, Opt. Exp., 2005
S. Zhang, PRL, 2005
J. Valentine et al, Nature, 2008
Cloaking: Fab. & Experiment
J. Valentine et al, pp 1-5, Nature, 2008
Future steps

Superlens


Hyperlens


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More applications
Overcoming diffraction limit in visible wavelength
Application to Bio-Engineering
Cloaking


Bulk-metamaterials characteristics
Manufacturing Issues
Questions?